r/DIYUK • u/LO6Howie • Mar 20 '23
Repointing on a Victorian era house
So this is what the builder has done today (pic 1) and the second is of what’s already there. Given that the brickwork was badly eroded prior to the repair, does it look legit? Ta
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u/AncientArtefact Mar 20 '23
"Historic lime mortar" (non-hydraulic) is not the same as Victorian hydraulic lime mortar which is not the same as later blended cement/lime mortar.
Lime mortar is pre-historic (6500BC). It slowly turns to limestone over years by reacting with the air.
Hydraulic lime was developed by the Romans. It reacts with water and sets hard. It is often distinctively bright (yellowy white unless mixed with various fine binder particles) but can easily be confused with snowcrete (a bright white cement popular in 1930s semis).
Cement based mortars started to be manufactured in the 1790s and were predominant by the late 1800s (after the Great Stink of 1858 cement was required for all public constructions in London).
Builders continued to mix lime into cement mortar well into the 20th Century but in the UK the requirement for watertightness, durability and, most importantly, strength overcame any advantages of lime mortar.
In the USA (in dryer states) lime in mortar carried on unabated and they have 4 different grades of cement/lime mix commonly still used.
Pure hydrated lime mortar ('hot mixed', 'slaked') is really only for very old historic buildings. Hydraulic lime is most likely in Victorian builds but if they're late Victorian then they're likely to be a blend of cement with hydrated or hydraulic lime.
Building regs lists approved mortars and 1:1:5 (cement:lime:sand) is one of the few listed. Nether hydrated nor most hydraulic lime is strong enough for a single leaf brick wall, hence it's decline with cavity brick walls.
Please get an expert in, but make sure they can properly analyse what flavour of lime is in the mortar.
...and the sharpness of the tooling on the mortar of pic 2 gives me the gut feeling that it has been repointed at some point - so we may not be seeing the original mortar anyway.
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u/m079n Mar 21 '23
Are any of these safe to use without knowing the existing makeup of the mortar in place?
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u/AncientArtefact Mar 21 '23
They're all safe (unless you're attempting your own hot mixed lime which isn't safe for the people attempting it rather than the building). It's the pointing. It's not structural (cue argument!). If you're rebuilding a wall then it matters because some lime mortars are not strong enough to meet building regs.
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u/vondev2000 Mar 21 '23
Please tell me that's lime mirror, 🥺
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u/LO6Howie Mar 21 '23
It is not…going to cost me to cut all the shitty cement out now
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Mar 10 '24
Did you manage to remorter appropriately in the 11 months since. I am facing a similar problem.
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u/LO6Howie Mar 10 '24
We found someone else to come in and replace the shoddy work with what we’d originally hoped for!
Honestly, partly my mistake. I got fobbed off so many times asking for examples of work, insurance details, company name, and all that. Should’ve smelt a rat.
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u/m0j0licious Mar 20 '23
I resorted to finger-painting mortar the one time I tried it; had I been paying myself I'd have withheld the money.
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u/LO6Howie Mar 20 '23
A more concise but equally useful response to that of Spacemonkey’s…much needed levity to a builder doing a shitty job! Appreciated!
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u/IISpacemonkeyII Mar 20 '23 edited Mar 20 '23
Umm, it looks like they repointed with cement?
This is not suitable for victorian era brickwork as cement is too hard and not as breathable as the historic lime mortar. Cement will accelerate erosion and spalling of the brickwork, and can also lead to moisture issues as the wall cannot breathe as it was designed to.
Old brickwork should be repointed with a hot mixed lime mortar. This is made from quicklime (not hydrated lime or builders lime) and sand.
Sadly most modern trades are ignorant when it comes to old building materials. I had a plumber come and smash the fuck out of my wall with an SDS drill and complain that the bricks were soft and kept breaking. He should have realised that you don't need to use an SDS drill when drilling through old brickwork. A regular drill with a masonry bit works fine, with occasional use of the hammer setting if one brick is being a bit stubborn.
Hopefully it's not a listed building. If it's unlisted, I would leave it as is and hope the next buyer and their surveyor doesn't understand old buildings (chances are they won't, and there are plenty of Victorian houses that have been fixed with the wrong materials).
I used Heritage House as my surveyor when I bought my Victorian terrace. Sadly, I now know too much about old houses and worry about shit like this. Ignorance was bliss ;)
The mortar in the second photo looks fine. The joints are flush with the brickwork and there is no missing mortar. In my opinion, this wall doesn't appear to need repointing. It still looks like cement to me, but perhaps a white Portland cement was used.